It will tell you the on chip temperature , hdd and motherboard temperature.

The on chip temp will tell you how effective is your cooling. It should be be below 55 degrees F.

If you want to see your Mini get hot do the following
1)Run an antivirus scan like Sophos or ClamAV and at the same time
2)Run a graphics benchmark like Unigine Heaven and turn on ALL the eye candy
http://unigine.com/products/heaven/download/